Oil piston damper



FIG. 1 is a front view of an oil piston damper showing my new design, a rear view being symmetrical to the front view;

FIG. 2 is a plan view thereof, a bottom view being same as the plan view;

FIG. 3 is a left side view thereof; and,

FIG. 4 is a right side view thereof. 

The ornamental design for an oil piston damper, as shown and described. 